In known lamps of this type, each filament lies in a plane transverse to the lamp axis or to the optical axis of the headlamp, respectively. When superimposed on a measurement screen for correct adjustment of the lower beam and with the lamp placed at the prescribed distance from the motor vehicle, the images generated by the headlamp of the lower beam filament provide a luminous field having a high intensity zone in the right-hand lower quadrant of the measuring coordinates whose boundary between bright and dark is blurred at the coordinate side near the center or zero point. This makes it difficult to precisely adapt or adjust the luminous field in and to the left upper corner of the right-hand lower quadrant of the measuring coordinates during the correct lower beam adjustment of the headlamp. Glare has to be scrupulously avoided; intense radiation emitted in the area above the abscissa of the measuring coordinates must not be present. As far as possible, no radiation should fall on the left-hand lower quadrant of the measuring coordinates near the center or zero point.